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The XHTML standard defines three Document Type
Definitions.
The most common is the XHTML Transitional.
The <!DOCTYPE> Is Mandatory
An XHTML document consists of three main parts:
- the DOCTYPE
- the Head
- the Body
The basic document structure is:
<!DOCTYPE ...>
<html>
<head>
<title>... </title>
</head>
<body> ... </body>
</html>
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The DOCTYPE declaration should always be the first line in an
XHTML document.
An XHTML Example
This is a simple (minimal) XHTML document:
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>simple document</title>
</head>
<body>
<p>a simple paragraph</p>
</body>
</html>
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The DOCTYPE declaration defines the document type:
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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The rest of the document looks like HTML:
<html>
<head>
<title>simple document</title>
</head>
<body>
<p>a simple paragraph</p>
</body>
</html>
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The 3 Document Type Definitions
- DTD specifies the syntax of a web page in SGML.
- DTD is used by SGML applications, such as HTML, to
specify rules that apply to the markup of documents of a
particular type, including a set of element and entity
declarations.
- XHTML is specified in an SGML document type definition
or 'DTD'.
- An XHTML DTD describes in precise, computer-readable
language, the allowed syntax and grammar of XHTML markup.
There are currently 3 XHTML document types:
- STRICT
- TRANSITIONAL
- FRAMESET
XHTML 1.0 specifies three XML document types that correspond
to three DTDs: Strict, Transitional, and Frameset.
XHTML 1.0 Strict
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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Use this when you want really clean markup, free of
presentational clutter. Use this together with Cascading Style
Sheets.
XHTML 1.0 Transitional
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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Use this when you need to take advantage of HTML's
presentational features and when you want to support browsers
that don't understand Cascading Style Sheets.
XHTML 1.0 Frameset
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
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Use this when you want to use HTML Frames to partition the
browser window into two or more frames. |
